Lifting-jack



JERMYW. BLISS, OF HARTFORD, CONNECTICUT.

LIFTINGr-JACK.

Specification of Letters Patent No. }0,663, dated March 21, 1854.

To all whom i may concern.'

Be it known that I, JERMY l/V. BLIss, of the city and county of Hartford, in the State of Connecticut, have invented a certain new and useful Improvement in Lifting or Forcing Jacks, of which the following is a full, clear, and exact description, reference being had to t-he accompanying drawing, which forms part of this specification, and in.

which- Figure l represents a frontor face elevation of my improved jack; Fig. 2, a top view or plan; Fig. 3, a side sectional elevation` taken throughthe line m a@ in Fig. l, and representing th-e working parts of the jack in the position they occupy when down or before commencing to lift; Fig. 4E, a similar view of the lifting portions of the ack when set or raised, and Fig. 5 a like view of the. said parts during the act of raising; Fig. 6` is a diagram of elbow jointed levels for ele-` Vating the lifting frame in contrast to the arrangements I employ for that purpose.

`i The jack represented in the accompanying drawing consists of two toothed `cams (A and B), the one of which (B) is pivoted to'the bottom of the lifting frame or slide (C),` while the other cam (A) is provided with journals that take their bearings in the side pieces or cheeksof the frame of the jack.

These cams gear into one another andthe lower o-ne is furnished with an operating handle or lever (a) that, as it is worked` downward causes the lower cam (A) to turni and similarly operate and raise the upperf frame affords great facility and security'of by insert-ing the lifting ban (c) in one of the lower cells or recesses (b) cam and with itthe lifting frame The lifting frame (C)- is provided with l feathers or guides which fit in slots in the jack frame and serve to preserve the lifting frame vertical as 1t rises.

lifting bar (c) and are of the same length, or thereabout, as the stroke of the jack. The outer or extreme ends vof the cams are flattened (as at e) and the lower cam is made.`

Cells` or barseats:` (b), one above the other, are made in the,I liftingl frame; these cells serve to carry the` cra (0 and of) of ,those rods; but, when operating or in mot-ion, the action of the 1f cams is greatly superior, for the purpose proposed, thanv an elevating jointed lever vmotion, as in commencing to lift (as in Fig. 3), the eifectlve or working angle of the camswhere they strain or gear into each other-:

is but slight or largely obtuseas compared with that of the elbow `jointed levers, as may be seen by reference to Fig. V6 in which the rods or levers (m and n) would-to produce the same length of stroke-be required to occupy the position represented by the lines m and n; and, in like manner, when the jack is at half stroke, or thereaboutv (as in'Fig.' 5), asimilar gain as'regardsthe working angle is obtained by the cams asl compared with the elbow jointed levers which would then occupy the position represented by the lines m2 and n2. fBut, in addition to the specified advantage ofobtaining a more effect-ive working angle, and the i consequent closer approximation to uniformity of speed or power throughout the stroke, all liab-ility of the cams to bend, as

in elbow jointed levers, is avoided, andV that injurious strain which is thrown upon' t-hev connecting joints of the said levers, when ythus operating, isby'the toothed gear of the cams (A and B) divided over several and yconstantly varying surfaces, whereby increased durability and security against i, breakage is obtained.

As a carriage jack, this construct-ion' and arrangement of the toothed cams and Ilifting op eration, as,

sof as to bearunder the axlel of the smallerpair of wheels-ofthe carriage, and working occupies 1n Fig. 4l, the carriage-is at once lifted by but a slight variation in the power exerted throughout the strokeand without requiringany troublesome or doubtful separate cont-rivance to lock the jack when raised as lit ,becomes self-setting, and in that respect is even more `secure thanv a yscrew of the necessary pitch to insure the same power or speed while it has the same facility of lowering as is claimed by the `ordinary rack and pinion jack, for, by only slightly elevating the working lever or handle so as to relieve the flattened or smooth extremities of the'cams,'the lifting frame (c) may then be run down by its own weight, or a spring (d) may be arranged to insure its inward motion and this arrangement of a spring is advisable when the jack is designed to force downward, at an inclination from the perpendicular, or horizontally, as under some circumstances of usin the jack it is required to do. The spring the cams remaining in theirproper relative positions to one another by keeping them constantly in gear, which otherwise, by the sticking of the lifting frame in its ldescent might not be the case and the cams be caused to slip a tooth or more by the swinging ofthe pivoted cam (B) backward so that upon again attempting to lift, the jack would fall short of its proper stroke and fail to set itself when raised by reason of the cams being improperly in gear and the flattened portions or extremities (e) of them failing to meet so as to form a set.

In the further use of the device as a carriage ack, after thefront wheels of the carriage have been cleaned, etc., the lifting bar (c) is next inserted in one' of the higher cells or recesses (b) of the lifting frame so as `to bring it 'to bear under thevaXle of the after or larger wheels, and the same operation of raising, setting and lowering performed as before, and thus great expedition and security is insured in raising and setting the carriage at its lift.

When the jack is required to lift beyond its `single or ordinary stroke, the `bar (c) is first inserted in the bottom c ell (b) `and a lift taken for 'the full stroke 'of the jack, when the body being raised is packed up from below to the elevation the jackhas by this one operation raised it; the lifting frame is then lowered and the bar (c) inserted in the next recess above, when another lift is taken, and so on in succession till the body is raised the full length of the lifting frame. The length of the cells being equal tothe stroke of the jack they serve as seats in succession for the lifting bar to act or bear against or under the body during each succeeding lift without involvingthe necessity of introducing intermediate packing between the lifting bar and the 'body or packing up the jack from beneath; and the several cells or seats serve generally to enlarge the convenience of the jack by giving to the lifting barseveral elevations from which to act, whether for carriage lifting or other purposes. Thus, it will be seen, the combination of the geared cams and 'cellular lifting frame, constructed and arranged as dealso serves to insure.,

be increased, according to the purpose it; is

designed to apply it,'without, as is customary with the rack and pinion jack, increasing friction and labor offitting by multiplying the number of parts, as the stroke of the lifting frame compared with the movement of the operating lever or handle is dependent upon the shape andpitchof the cams, while the selfsetting arrangement of the cams avoids the usual loss of time, and trouble, in locking the jack, when raised, by separate devices for that purpose; and al] tendency on the part of the jack to fly from its set is obviated by reason ofthe broad bearing surface which is given to the earns` at their flattened extremities (e) and the division of the resistance or pressure on either side of the axes of the cams as well as in a direct line with their centers, as represented in the drawing. The gearing of the portion of the lifting frame to produce but little friction and gives a free and easy action to the frame, both in ascending and descending, and occasions but little wear by dividing the lifting pressurevover several teeth or surfaces at a time.

s ForV some purposes, it is obvious, the cellular construction of the lifting` frame may be dispensed with and thefsliding orV lifting frame be made solid and caused to act direct under the body to be raised, but in a general way I prefer interposing a lifting bar and constructingl the lift-ing frame with cells, or their. equivalents, arrangedas described for the purposes specified.

y What I claim as new in my invention, and useful, andl desire to secure by Letters Patent,"isl l The combination of the toothed cams (A and B) with the lifting frame or slide (C) arranged and operatingttogether as and for the purposes set forth, when the said cams are so constructed at their finishing extremities (e) as to formfa bearing surface on either sideof the centers of the axes of the cams whereby the jack is made self setting arid is restrained from flying from its set as specified.

In .testimony whereof, jI have hereunto subscribed my name.

, JERMY w. Buss. l

`Witnesses: n

SAMUEL F. JONES, AJOSEPH McDoNALD. 

